Monday, October 27, 2008

As I mentioned in a previous post, my thesis was on an experiment called BaBar... as things go in particle physics, just because you're "done" with your previous job/experiment doesn't mean all of the loose ends are completely wrapped up. My loose end was a 15-page journal article on my thesis research, and I'm now happy to say that it was accepted to a journal called Physical Review D and will be published shortly:

Dear Dr. Majewski:

The manuscript "Measurements of B(B0 → Λc+p) and B(B- → Λc+p π-) and studies of Λc+π- resonances" by Aubert, B. et al. is being accepted for publication in Physical Review D...

Sincerely,

Urs M. Heller Associate Editor Physical Review D

It's a little sad, because it marks the formal end of my time on BaBar, but it feels pretty good to have the paper finished and accepted. (Plus, even a year later it's still pretty cool to be addressed as "Dr. Majewski"...) Time to celebrate!

Friday, October 24, 2008

The observant among you might notice that my monitor counter is gone. That's because it's here! 50 days and a 70 euro tax later..... (grumble, grumble).

However, a couple people emailed/pointed out this Nature article about how peeling sticky tape generates x-rays. Although it's not really related to the LHC, it's pretty cool, and they have a video! Here's the short version:

On 19 September 2008, during powering tests of the main dipole circuit in Sector 3-4 of the LHC, a fault occurred in the electrical bus connection in the region between a dipole and a quadrupole, resulting in mechanical damage and release of helium from the magnet cold mass into the tunnel. Proper safety procedures were in force, the safety systems performed as expected, and no-one was put at risk....

During the ramping-up of current in the main dipole circuit at the nominal rate of 10 A/s, a resistive zone developed leading in less than one second to a resistive voltage of 1 V at 9 kA. The power supply, unable to maintain the current ramp, tripped off and the energy discharge switch opened, inserting dump resistors into the circuit to produce a fast current decrease.... Within one second, an electrical arc developed, puncturing the helium enclosure and leading to a release of helium into the insulation vacuum of the cryostat.... The spring-loaded relief discs on the vacuum enclosure opened when the pressure exceeded atmospheric, thus releasing helium into the tunnel...

At the bottom of the press release, they define the term cold mass:

The magnets, equipped with their helium vessel and end covers, constitute the "cold masses".... The weight of the cold mass is transmitted to the vacuum enclosure via cold support posts and is further transmitted to the tunnel floor by adjustable support jacks, anchored in the concrete.

Here is an illustration of the electrical connection between the two magnets where the resistance developed:

The press release goes on to itemize the damage, which I've arranged into a list:

"contamination by soot-like dust which propagated over some distance in the beam pipes"

"damage to the multilayer insulation blankets of the cryostats" (the magnet "sleeves")

"the cryostats housing [the] quadrupoles broke their anchors in the concrete floor of the tunnel and were moved away from their original positions"

"the electric and fluid connections pull[ed] the dipole cold masses in the subsector from the cold internal supports inside their undisplaced cryostats"

"the displacement of the quadrupoles cryostats damaged "jumper" connections to the cryogenic distribution line, but without rupturing its insulation vacuum"

The bottom line is that "at most 5 quadrupoles and 24 dipoles" [magnets] need to be fixed, and they need to be brought out of the tunnel and up to the surface for that to happen. They also say that more magnets might need to be cleaned (from that "soot-like dust") and get new "multilayer insulation" (new "sleeves"); these might need to come up to the surface, or they are considering trying to clean the magnets in place in the tunnel. The good news is that "Spare magnets and spare components appear to be available in adequate types and sufficient quantities to allow replacement of the damaged ones..." So let's be optimistic that everything will be fixed in time to start up again next spring!

Thursday, October 16, 2008

So, since I'm a chick, and a physicist, the whole "women in science" issue is important to me. Basically, I think we need more of them :) And recently I have been consumed by election fever (watching the debates, filling out my foreign absentee ballot), as I'm sure many of you have been. So I thought it was particularly interesting that over the summer, the Association for Women in Science asked each candidate a bunch of questions about women in science ... and, this week the candidates responded (which I thought was amazing, frankly). Here's an excerpt from the full questions and responses:

In a September 2006 report, Beyond Bias and Barriers: Fulfilling the Potential of Women in Academic Science and Engineering, the National Academies stated that, in order to maintain scientific and engineering leadership amid increasing economic and educational globalization, the United States must aggressively pursue the innovative capacity of all people, regardless of sex. Although women make up almost half of the U.S. workforce, they continue to be underrepresented in STEM professions, particularly in the higher academic faculty ranks and leadership positions. As President of the United States, how do you plan to address the need for more women in STEM?

Sen. Barack Obama:

Joe Biden and I agree with the conclusion of the National Academies’ Bias and Barriers report that the United States must aggressively pursue the innovative capacity of all people. In a globalized world, our prosperity and national security depend on our ability to lead the world in innovation. Other nations are now challenging that leadership, and in responding we must call upon talent and creativity of all of our people. We will need to significantly increase our STEM workforce, and to do that we will need to engage not just women and minorities but also persons with disabilities, English language learners, and students from low income families.

Women are significantly underrepresented in the STEM workforce, and especially in the leadership positions in research and academia. We need women in leadership roles both for their contribution and for the message of encouragement and opportunity that their presence sends to our daughters. We support a range of proactive measures that will open opportunities in science to women, such as requiring minority and female representation on government panels developing innovation and competitiveness strategies, and establishing mentoring programs to support women and underrepresented groups in STEM education programs ­- two measures that I helped pass as part of the America COMPETES Act. We also support improved educational opportunities for all students, increased responsibilities and accountability for those receiving federal research funding, equitable enforcement of existing laws such as Title IX, continuation and strengthening of programs aimed at broader engagement in the STEM disciplines, full funding for the America COMPETES Act, and increased funding for the National Institutes of Health.

Sen. John McCain:

I am committed to ensuring a diverse workforce. Discrimination on the basis of sex is abhorrent, and my administration will vigorously enforce federal anti­-discrimination laws. All people should have the opportunity to reach their potential based on merit and hard work.

It is also important that we strengthen our public education system’s focus on math, science, and engineering to spark children’s interest in those important fields. That is why I have proposed a dramatic overhaul of Title II of No Child Left Behind to provide funding for incentive bonuses for teachers who choose to teach those subjects. I also support providing funding for low­-income students to hire tutors and for local districts to expand online educational opportunities—initiatives that will ensure that learning continues outside of the classroom.

Tuesday, October 14, 2008

It's been a while since I've posted last, and I guess that's mostly because things have quieted down quite a bit. Physics is kind of same-o, same-o. I've finally settled into a bit of a routine, getting used to not having a car (and successfully getting a monthly bus pass), appropriately caffeinating myself throughout the day (too many cups of strong European coffee makes you feel all jittery and unstable...), and figuring out when on earth to get groceries. Actually, I'm still not used to that part yet ... grocery stores here are only open until 7:30pm (for the close one) or 9pm (for the farther one) during the week, all day on Saturday, and they are mostly closed on Sunday. None of this 24-hour, get it whenever you want it culture. I did finally find a small store that's open on Sunday for those emergency purchases. I guess Sunday is really supposed to be a chill day, so this past one we tried to embrace that by cramming a gaggle of physicists into our living room for brunch... almost 3 loaves of brioche later, we successfully stuffed ourselves with "french toast", mimosas, and good conversation. Even the french toast was a challenge, because we had to trek all the way to Geneva to the American Market for brown sugar (and splurged on some authentic Mrs. Butterworth).

My biggest outstanding complaint is that my own personal 2-year-old computer monitor that I shipped to myself on September 4th still hasn't arrived. Apparently it's been in French Customs since September 10th! From various google searches, this sort of delay is completely normal, and they'll probably eventually send me a letter asking for so many € to claim it. So I thought I'd start a little counter on the left to keep track of how long it's been since I mailed it... at this point, it's so ridiculous it's humorous.

Thursday, October 2, 2008

Yesterday was moving day, so after some heavy lifting I am finally moved in to my new apartment. It's a fully-furnished 2-bedroom in France, about a block from a bus stop so I will continue to take the bus to and from work. (I also have a CERN bike that I can use, but so far laziness has won in the mornings...) It's a lovely fall day today, and the Cubs are in the playoffs, so life is good.

It's been pretty quiet here at CERN. The lawsuit against the LHC was thrown out of court, previously scheduled meetings are continuing (even though they don't seem quite as urgent without beams), and it seems like everyone has settled back into their routines.

On the funding front, Congress has passed a continuing resolution until March of 2009, which means that the funding levels for science stay at the same level as FY08 (FY=fiscal year, which starts on October 1 ... we're now in FY09). These continuing resolutions are always tough because we don't even get a 3% boost to compensate for inflation. But the funding agencies and national labs weren't surprised; this is an election year, after all, so no one expected a new budget until we have a new president. In my opinion, this yearly budget thing seems pretty antiquated, and doesn't really work for science because it doesn't provide the funding continuity needed for long-term projects. Of course, I don't mean to sound ungrateful for the support we get from Congress, but it feels like they never pass the budget by October 1 anyway.... check out this plot from the Dept of Energy Office of Science website of how "on time" Congress has been with the budget over the past 30 years (green is early, red is late):

The past 8 years are kind of appalling if you ask me. Can you imagine paying your rent or your mortgage 150 days late?

Subscribe

Search This Blog

About Me

I'm a post-doc in particle physics at Brookhaven National Laboratory in Upton, NY. I work on the ATLAS experiment at CERN, and I am stationed at CERN for at least a year... ok more like 2 at this point...